/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.aop.aspectj;

import org.aopalliance.aop.Advice;

import org.springframework.aop.Advisor;
import org.springframework.aop.AfterAdvice;
import org.springframework.aop.BeforeAdvice;
import org.springframework.lang.Nullable;

/**
 * Utility methods for dealing with AspectJ advisors.
 *
 * @author Adrian Colyer
 * @author Juergen Hoeller
 * @since 2.0
 */
public abstract class AspectJAopUtils {

    /**
     * Return {@code true} if the advisor is a form of before advice.
     */
    public static boolean isBeforeAdvice(Advisor anAdvisor) {
        AspectJPrecedenceInformation precedenceInfo = getAspectJPrecedenceInformationFor(anAdvisor);
        if (precedenceInfo != null) {
            return precedenceInfo.isBeforeAdvice();
        }
        return (anAdvisor.getAdvice() instanceof BeforeAdvice);
    }

    /**
     * Return {@code true} if the advisor is a form of after advice.
     */
    public static boolean isAfterAdvice(Advisor anAdvisor) {
        AspectJPrecedenceInformation precedenceInfo = getAspectJPrecedenceInformationFor(anAdvisor);
        if (precedenceInfo != null) {
            return precedenceInfo.isAfterAdvice();
        }
        return (anAdvisor.getAdvice() instanceof AfterAdvice);
    }

    /**
     * Return the AspectJPrecedenceInformation provided by this advisor or its advice.
     * If neither the advisor nor the advice have precedence information, this method
     * will return {@code null}.
     */
    @Nullable
    public static AspectJPrecedenceInformation getAspectJPrecedenceInformationFor(Advisor anAdvisor) {
        if (anAdvisor instanceof AspectJPrecedenceInformation) {
            return (AspectJPrecedenceInformation) anAdvisor;
        }
        Advice advice = anAdvisor.getAdvice();
        if (advice instanceof AspectJPrecedenceInformation) {
            return (AspectJPrecedenceInformation) advice;
        }
        return null;
    }

}
